One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(6,10)(7,8)(11,12)(13,14,18,21,19,16,17,22)(15,23,25,20,27,28,26,24)(2,4)(5,6)(7,10)(8,12)(9,11)(13,15,18,25,19,27,17,26)(14,20,21,28,16,24,22,23)(5,6)(7,10)(8,12)(9,11)(13,16)(14,19)(15,24)(17,21)(18,22)(20,27)(23,25)(26,28) involution — undirected(5,7,9,8)(6,10,11,12)(13,17,19,18)(14,21,16,22)(15,25,27,26)(20,23,24,28)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.